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Abstract Previous work has demonstrated the feasibility of performing spatially resolved luminescence measurements with sliced solid materials (e.g., rock and ceramic) to determine the cumulative absorbed dose to individual luminescent grains in situ. In the present study, aspects of the dosimetry of individual grains that are truncated during slicing were examined using radiation transport simulations employing simplified geometries. The results of the simulations were applied to model the effect of grain truncation on the dosimetry of grains, in particular the beta attenuation factor and the laboratory beta source dose rate for whole and partial volumes of individual spherical grains. Where a material contains a wide range of coarse grain sizes there is the potential for misinterpreting the size of the parent grain on the basis of an examination of the shape and size of the truncated grain section exposed in the slice surface. If the original grain size is underestimated, which is likely, the simulations predict an overestimation of both the beta attenuation factor and the laboratory source beta dose rate, the maximum extent of which depends on the range of grain sizes present in the material. The simulations also indicate that by limiting the depth from the surface within which the average absorbed dose is determined, approximating the effects of opacity of the mineral, the magnitude of these deviations is reduced. However, a consequence of particular interest deriving from these results is that, when evaluating the age equation, the changes in the two quantities compensate, acting to moderate the overall effect on the calculated age for an individual grain, depending on the geometry of the grain and the composition of the sample material. Highlights • This study examined an aspect of in situ single grain dating of minerals within sliced solid samples. • Grain truncation potentially affects values of both the beta attenuation factor and the laboratory beta source dose rate. • Radiation transport simulations were used to examine the effect of grain truncation on beta dose rate assessment. [ABSTRACT FROM AUTHOR]

Abstract The beta-particle emission from a sediment or rock sample can be measured very precisely using beta-counting instruments. The observed count rate is largely a function of the radionuclide concentration in the sample, so has the potential to provide a precise estimate of the natural radiation dose rate. However, the count rate is also sensitive to the attenuation of beta particles in the sample, and the relative proportions of the different radionuclide sources. Here we devise a correction for the self-attenuation effect using dilution analysis, and show that imprecise prior knowledge of radionuclide activity is sufficient for calculation of an accurate combined beta-plus-gamma dry dose rate. The method is tested on a selection of archive samples, and compared with results from high-resolution gamma-spectrometry. We show that with counting uncertainty ∼2%, and calibration uncertainty ∼2%, the total random uncertainty of the beta-plus-gamma dry dose rate is less than 3%. For most natural sediments, this level of precision equal to, or better than, that obtainable with other methods. Highlights • We design a method to obtain high-precision beta-plus-gamma dose rate estimates for natural sediment. • We use beta-counting instruments, which are simple to operate and relatively cheap. • Prior information is required on the relative strength of the K, U and Th sources. • The sediment stopping power can be corrected for using dilution analysis. [ABSTRACT FROM AUTHOR]

Abstract The ability to deliver accurate and precise calibration doses is a central part of all trapped charge dating methods. Usually, the radiation source (α, β, X-ray) used to deliver these doses is, in turn, calibrated against an absolutely known reference source (usually a γ source) and many laboratories make use of Risø calibration quartz for this purpose. We have previously described this material in detail (Hansen et al., 2015) and discussed the over-dispersion (OD) of 3.2 ± 0.3% in calibrated dose rate observed over 16 years. This dispersion highlights the danger of relying on individual calibrations, and is clearly undesirable. Here we continue our investigation into providing reliable calibration materials for trapped electron dating. A comparison of the apparent quartz β source dose rates shows that there is no significant dependence on the geological source of the quartz. However the β dose rate decreases by 25% with increasing grain size from about 100 μm to 1 mm, and backscatter leads to a dose rate increase of ∼1% per unit atomic number of the substrate. It is concluded that, for the multi-grain aliquots used in this study, the contributions to dose rate variability from grain size and substrate variations are likely to be negligible. Nevertheless there may be a practical advantage in using a high Z substrate because of the higher dose rate. Finally we test the measured to given dose (dose recovery) ratio for five heated feldspar samples and use the pIRIR 290 signal for β source calibration; surprisingly this gives an apparent β dose rate 15% lower than that to quartz despite their almost identical stopping power and mass absorption characteristics. Our results are discussed in terms of their significance for reproducibility and accuracy of β dose-rate estimates. Highlights • The average apparent quartz dose rate is independent of the source of the quartz. • The effect of likely grain size and substrate variations on β dose rate reproducibility is probably not significant. • It may be possible to increase effective β source dose rates by ∼40% using platinum a substrate. • The apparent β dose rate to feldspar is ∼15% less than that to quartz, independent of origin. [ABSTRACT FROM AUTHOR]

Abstract The dating of materials using stored dose methods requires accurate determination of the environmental dose rate. The calculation of dose rates from radionuclide concentrations requires conversion parameters derived from nuclear data (half life, decay energies and intensities, and branching ratios). With the substantial body of primary data, it is convenient to use data from evaluated libraries. These libraries show variations reflecting both newer data unavailable to earlier evaluations and the relative importance given to different data sets by the evaluators. Commonly used conversion parameters derive from the Evaluated Nuclear Structure Data File (ENSDF), either directly or from secondary publications, with new tabulations produced in recent years following revisions to this library. Other international evaluations of nuclear data include the NEA/OECD supported JEF2.2 and JEFF3.11 evaluations, and the Decay Data Evaluation Project (DDEP). A technique comparing different evaluations to identify data that can not be confidently used has been developed. These differences have been investigated with an evaluation of underlying nuclear data. Particular radionuclides of interest are discussed; 214Bi where recent evaluations depend on a single high precision data set, 228Ac where the decay scheme is incomplete and further measurements are required, and 40K where the mean beta energy has been calculated in the evaluations using an incorrect shape factor. Revised dose rate conversion factors have been produced, which are largely consistent with earlier values with the exception of the 40K beta parameter which is 4% higher than recent values but consistent with earlier calculations. Highlights • Innovative comparison of evaluated libraries to highlight lower confidence data. • Highlighted radionuclides with lowest confidence data - 214Bi, 228Ac, 40K • 40K beta spectrum incorrect in all evaluated libraries, improved mean energy given. • Revised dose rate conversion factors using best available data given. [ABSTRACT FROM AUTHOR]

A Monte Carlo electron transport code PENELOPE was used to analyze beta particle energy deposition in semiconductors for titanium tritide and beryllium tritide. The source thickness was incorporated into the model in order to take into account the self-absorption of beta particles in the source material. Furthermore, an isotropic source was modeled with the full beta energy spectrum of tritium to make the beta particle transport method more realistic. The simulated results for a 0.4- $\mu \text{m}$ -thick titanium tritide source with silicon carbide agreed well with the experimental results. The simulated results obtained for an optimized 2.5- $\mu \text{m}$ -thick beryllium tritide source with silicon carbide was about two times higher than the power for a 0.4- $\mu \text{m}$ -thick titanium tritide source with silicon carbide. An approximately two times higher short-circuit current density was obtained for beryllium tritide with silicon compared to silicon carbide. However, the power output density was about $10\times $ higher for silicon carbide. The width of the depletion region for a p-type dopant concentration of $\textsf {1} \times \textsf {10}^{\textsf {19}}/\textsf {cm}^{\textsf {3}}$ and an n-type dopant concentration of $\textsf {5} \times \textsf {10}^{\textsf {14}}/\textsf {cm}^{\textsf {3}}$ is about 1.4 and $2.5~\mu \text{m}$ in silicon and silicon carbide, respectively. The estimated beta particle penetration depth is about 1.48 ± 0.015 and $\textsf {1.03} \pm \textsf {0.015}~\mu \text{m}$ in silicon and silicon carbide, respectively. This suggests that the proper choice of dopant concentrations will achieve greater energy deposition in the depletion region, which in turn will increase the power output. [ABSTRACT FROM AUTHOR]

Abstract We previously developed a radiation detector using a ceramic scintillator made for X-ray computed tomography (CT), Gd 3 (GaAl) 5 O 12 :Ce (GGAG), combined with a position-sensitive photomultiplier tube (PSPMT) for the imaging of radiation. However, GGAG's scintillation wavelength is more suitable for silicon-based photodetectors than PSPMT, and so better performance is expected by combining it with a silicon-based photodetector. Therefore, here we combined a GGAG plate with silicon photomultiplier (Si-PM) arrays to develop a radiation-imaging detector. Our proposed Si-PM-based GGAG radiation-imaging detector consists of a 0.5-mm-thick GGAG plate, a light guide, and an 8 x 8 Si-PM array. The spatial resolutions of this imaging detector surpassed 0.31-mm FWHM for 5.5-MeV alpha particles. The spatial resolution of the Sr-Y-90 beta particles (maximum energy: 2.28 MeV) was ∼0.8 mm FWHM and 0.6-mm FWHM for Ca-45 (maximum energy: 0.24 MeV). The spatial resolutions for Co-57 (122 keV), Am-241 gamma photons (60 keV), and Cs-137 X-rays (∼35 keV) were 0.6-, 0.8-, and 1.0-mm FWHM, respectively. Since GGAG's scintillation decay curves for alpha particles are different from gamma photons or beta particles, we can use pulse-shape discrimination to separate the Am-241 alpha particles from the Cs-137 gamma photons as well as from the Sr-Y-90 beta particles. Highlights • We developed a radiation imaging detector using a GGAG plate combined with Si-PM arrays. • Developed radiation-imaging detector achieved 0.3 mm FWHM for 5.5 MeV alpha particles. • Separation of the alpha particles and gamma photons or beta particles was possible by using the pulse shape discrimination. [ABSTRACT FROM AUTHOR]

Summary: A method for discriminating between the counting rates attributable to beta rays and gamma rays was proposed. The method was based on the characterization of the sensitivity ratios of multiple scintillators. Four scintillators were used in this study: 10 and 20‐mm bismuth germanate and plastic scintillators. The sensitivity ratios of two scintillators with different elemental compositions can provide more information related to the energy of the incident photon, and scintillators with different thicknesses can provide a constant parameter which is necessary in the calculation of the beta‐ray and gamma‐ray counting fractions. A mixed source containing 60Co and 90Sr was used to estimate the accuracy of the proposed method. The gamma‐ray counting fraction was successfully deduced with a relative error of 2.01%. The method is expected to be used for cost‐effective assessment of radioactive waste resources and conservative estimation of the radioactivity of pure beta‐emitting radionuclides. A method for discriminating between the counting rates attributable to beta rays and gamma rays was proposed. The method was based on the characterization of the sensitivity ratios to gamma and beta rays for four scintillators: 10 and 20 mm, bismuth germanate and plastic scintillators. The fraction of the gamma‐ray counting rate using a combined 60Co and 90Sr source was successfully deduced with a relative error of 2.01%. [ABSTRACT FROM AUTHOR]

Radiochemistry laboratories are one of the most destructive nuclear facilities in Iraq. It is contaminated by many isotopes that emit alpha or beta particles. The indoor air of radiochemistry laboratories was monitored to determine alpha and beta concentrations by used the alpha/beta intelligent Continuous Air Monitor (iCAM) device. Alpha airborne particulates come from radon/thoron, whereas beta comes from background compensation. The concentration of R-222 and Rn-220 was found to be high in most samples measured inside the radiochemistry building, ranging from 12 to 52, and 0.08 to 0.41 respectively. The annual effective dose of exposure to radon and thoron ranged from 0.03 to 0.188. The concentration of radon and annual effective dose for workers are close to anxiety levels, especially in laboratories C1 and C2, since there is no guaranteed of good air exchange. [ABSTRACT FROM AUTHOR]

Abstract Our research group has developed a thermoluminescence dosimeter (TLD) based on pellets of LiF:Mg,Ti mixed with polytetrafluoroethylene (LiF:Mg,Ti +PTFE). This TLD can be used as a personal dosimeter. Extensive type testing, carried out with reference to the International Electrotechnical Commission (IEC) Standard, were performed for the purpose of accepting the LiF:Mg,Ti+PTFE as a personal TL dosimeter. Tests performed include repeatability, batch homogeneity, linearity, detection threshold, and light sensitivity. Results showed that locally made LiF:Mg,Ti+PTFE TLDs met all the standard requirements. Highlights • Type testing were performed to locally made LiF: Mg,Ti+PTFE dosimeters. • Tests were performed according to IEC 62387 Standard. • The dosimeter passes the entire test requirement with very good performance. [ABSTRACT FROM AUTHOR]

Abstract To date, artificial neural networks have become firmly established in those areas where the use of conventional algorithmic solutions is limited or impossible. Detection of alpha-active and beta-active nuclide contamination is important in radiation ecology medicine, because such contamination produces strong biological effects on humans. An interesting application of artificial neural networks is the recognition of the type of ionizing radiation based on air ion method. Negative ions from the alpha particle tracks are detected by the open-air gas-discharge counter. Ion clusters being transferred from the particle tracks to the detector volume by an air flux. Avalanche multiplication of detached electrons from air ions allows to achieve a large gain. Background radiation can be characterized as irregular, with a small frequency of pulses of small amplitude (small power of the amplitude spectrum), while ionization from alpha particles is characterized by irregularity (low-active alpha particles), accuracy of pulses (very large number of them at a certain interval), large amplitude (large power of the amplitude spectrum). The ionization of beta particles is characterized by the regularity (due to the greater path length and closed air volume) and medium amplitude spectrum power. [ABSTRACT FROM AUTHOR]

This paper demonstrates the ability of diamond sensors to respond to beta radiation. A Chemical Vapor Deposition (CVD) single crystal diamond was used in this work. The diamond crystal has a dimension of 4.5 × 4.5 by 0.5  mm thick. Metal contacts were fabricated on both sides of the diamond using titanium and palladium metals with thicknesses of 50 nm and 150 nm, respectively. The energy response of the diamond sensor was experimentally measured using three beta isotopes that cover the entire range of beta energy: 147 Pm, a weak beta radiation with a maximum energy of 0.225 MeV, 2 ° 4 Tl, a medium energy beta radiation with a maximum energy of 0.763 MeV, and 9 °Sr/ 9 °Y, with both a medium energy beta radiation with a maximum energy of 0.546 MeV, and a high energy beta radiation with a maximum energy of 2.274 MeV. The beta measurements indicate that diamond sensors are sensitive to beta radiation and are suitable for beta spectroscopy. This is important in estimating dose since diamond is tissue equivalent, and the absorbed dose is easily determined from the energy and the mass of the active volume. The high energy betas from 2 ° 4 Tl and 90 Sr/ 90 Y penetrates the sensor without depositing sufficient energy in the active area because their range is larger than the thickness of sensor. The sensitivity of the detector is limited because of its small volume and can be improved by combining smaller area sensors since growing large size diamond is currently a challenge. [ABSTRACT FROM AUTHOR]

In this work, the thermoluminescence (TL) characterization of pellet-shaped ZnO:Na phosphors synthesized through a controlled chemical reaction followed by thermal annealing at 900 °C in air is reported. X-Ray diffraction patterns reveal ZnO hexagonal zincite structure for the samples, some of which were exposed to beta particle irradiation in the dose range from 0.08 to 2048 Gy in order to study their TL features. The synthesized ZnO:Na samples are more than 200 times more sensitive than ZnO samples synthesized by the same method, and present a 0.02 (1/50) sensitivity relative to the TLD-100 dosimeter. [ABSTRACT FROM AUTHOR]

In this work, we report for the very first time on the thermoluminescence (TL) and afterglow (AG) properties of Li 2 ZrO 3 . The ternary oxide Li 2 ZrO 3 was synthesized by solid state reaction of a mixture of Li 2 CO 3 and ZrO 2 subjected to thermal annealing at 400 °C for 2 h and 1000 °C during 24 h in air. The characteristic glow curves of beta particle irradiated samples exhibit an intense TL emission located around 150 °C. From the shape of the TL curve, a 0.4 form factor was determined, suggesting that first order kinetics processes are involved. The afterglow decay curves were recorded after exposure to beta particle irradiation in the dose range from 0.5 up to 2 kGy. The AG integrated in the time interval from 510 to 600 s after radiation exposure shows a linear dependence as a function of the irradiation dose from 0.5 up to 256 Gy. A method is proposed to compute the lower detection limit and the AG sensitivity and applied to the studied phosphors. Structural and morphological characterization were carried out by X-ray diffraction and Scanning Electron Microscopy, respectively. From the results presented, it is concluded that the AG response of the synthesized Li 2 ZrO 3 presents features suitable to develop radiation detectors and dosimeters. [ABSTRACT FROM AUTHOR]

In this work, we report on the afterglow (AG) response characterization of commercially available ZrO 2 . Pellet shaped samples previously annealed in air at 1000 °C during 24 h were exposed to beta particle irradiation in the dose range from 0.5 up to 128 Gy and their AG decay curves recorded during 600 s after irradiation exposure. The characteristic glow curves of beta particle irradiated ZrO 2 show two maxima located around 80 °C and 150 °C. The first one rapidly vanishes at room temperature, giving rise to AG. The integrated AG signal increases as dose increases from 0.5 to 128 Gy, with a linear dependence from 0.5 up to ca . 32 Gy. Excellent reproducibility of the AG response was observed in 10 irradiation – AG readout cycles, showing that the studied ZrO 2 samples are reusable. The results here presented show that ZrO 2 is a promising material for use as a radiation dosimeter based on the AG phenomenon. [ABSTRACT FROM AUTHOR]

This work discusses synthesis of stable α-phase of Al 2 O 3 :Tm 3+ by combustion method using temperature controlled microwave oven. The crystalline phase was analyzed by X-ray diffraction (XRD) technique and average crystallite size was found to be 147 nm. Observations using scanning electron microscope (SEM) image suggest formation of agglomerated particles and energy dispersive x-ray spectroscopy (EDS) confirmed the incorporation of Tm 3+ in Al 2 O 3 . Thermoluminescence emission (TLE) spectrum of γ – irradiated Al 2 O 3 :Tm 3+ shows characteristic emissions of Tm 3+ , Cr 3+ and Mn 4+ . TL glow curves of γ – irradiated Al 2 O 3 :Tm 3+ exhibit a prominent peak at 453 K along with a shoulder at 496 K. The glow curves of β – irradiated Al 2 O 3 :Tm 3+ were studied in different emission regions using U340 + BG39 (UV band pass), CS759 + BG39 (Blue band pass) and BG39 (Visible band pass) optical glass filters. A prominent peak was observed at 471 K in for all mentioned emission regions and an additional shoulder was observed at 511 K with CS759 + BG39 and BG39 filters. TL glow curve of β – irradiated Al 2 O 3 :Tm 3+ using only BG39 filter had more counts than CS759 + BG39 and U340 + BG39 filters. Further, the effect of Tm 3+ impurity on TL response was studied. TL kinetic parameters were estimated by using computerized glow curve deconvolution (CGCD) technique. The activation energy and frequency factor of prominent peak (471 K) were found to be 1.31 eV and 3.50 × 10 13  s −1 respectively. Optically stimulated luminescence (OSL) characteristics of β – irradiated Al 2 O 3 :Tm 3+ were studied using U340 + BG39 and CS759 + BG39 filters. Highest OSL intensity was observed in UV. OSL curves were deconvoluted by general order decay equation. Life time and photoionization cross section of the traps responsible for OSL were found to be 5.30 s and 3.98 × 10 −18  cm 2 respectively. The process of ionization of electron from Tm 3+ , electron trap in host lattice and its recombination mechanism is proposed. Phosphorescence decay of beta irradiated sample was also studied. The lifetime of phosphorescence decay was found to be 140 s for the prominent peak and TL intensity decays 25% after the phosphorescence. TL/OSL dosimetric properties viz. linearity with dose, reusability and minimum detectable dose of the phosphor were characterized for medical dosimetry application. [ABSTRACT FROM AUTHOR]

This study is mainly centered on thermoluminescence (TL) behavior under beta excitation at room temperature (RT) of Sm 3+ activated ZnB 2 O 4 phosphors synthesized by low temperature chemical synthesis method. The prepared phosphors were characterized by the X-ray powder diffraction (XRD) method. The effects of dopant concentration, beta radiation dose (0.115–69 Gy) and heating rate (0.5–10 °C/s) on TL intensity of Sm 3+ doped ZnB 2 O 4 phosphors and reproducibility are investigated using a lexsyg smart TL/OSL reader system. The activation energy values, E obtained from the analysis of the TL glow curve were calculated with initial rise (IR) method and peak shape (PS) method over the deconvoluted glow curves. The E a – T stop and CGCD methods indicated that the glow curve of this phosphor is the superposition of at least six components, which were called to as P1–P6, in the temperature range between RT and 400 °C. The results reveal that 2% Sm 3+ doped ZnB 2 O 4 gives optimum TL response, the relative intensity of the glow peak increases linearly with increase of beta dose and, the peaks of TL glow curves shift towards the higher temperature side with increase in heating rate as the total area under the glow peak remains the same. The maximum variation of reproducibility for ten successive irradiation cycles of 20.7 Gy is less than 3% from the average value and the sample doped 2% Sm 3+ shows a good stability for the reusability. Additionally, the results obtained from IR and PS methods indicates that the complex glow curve is composed of six distinguishable peaks. [ABSTRACT FROM AUTHOR]

Pb-210, a highly-toxic radionuclide, is widely distributed in environments and is commonly the target for monitoring. In this paper, a modified method for determining Pb-210 radioactivities in plants in China has been presented. The procedure involves digesting the plant samples by microwave directly, separating Pb-210 from Bi-210 and Po-210 with Sr resins, and measuring the beta particles using liquid scintillation counting (LSC). Compared to previously reported approaches, this method uses no hydrochloric acids which are restricted in China and involves no co-precipitation. The entire procedure could be finished within 1 day with a radiochemical yield of 70%. The lower limit of detection for Pb-210 was found to be 38.0 mBq/g for a counting time of 72,000 s. The method was tested using a standard solution and plant samples. LSC spectra indicate that Pb-210 is effectively stripped and the results are consistent with those obtained from the gamma-spectrometry. [ABSTRACT FROM AUTHOR]

Twelve types of chemical fertilizers commonly used in the south of Vietnam were collected for analysis. It was found that the activity concentration of 226Ra was in the range from below detectable level (BDL) to 139 Bq kg−1 while gross alpha and gross beta activities were in the ranges from BDL—691 Bq kg−1 and BDL—18753 Bq kg−1 respectively. The correlation was found between gross alpha activity and activity concentration of 226Ra in most of fertilizers. The radiological hazard due to application of fertilizers is insignificantly under the agricultural conditions. [ABSTRACT FROM AUTHOR]

Summary: A Monte Carlo source model using PENELOPE was developed to investigate different tritiated metals in order to design a better radioisotope source for betavoltaic batteries. The source model takes into account the self‐absorption of beta particles in the source which is a major factor for an efficient source design. The average beta energy, beta flux, source power output, and source efficiency were estimated for various source thicknesses. The simulated results for titanium tritide with 0° and 90° angular distributions of beta particles were validated with experimental results. The importance of the backscattering effect due to isotropic particle emission was analyzed. The results showed that the normalized average beta energy increases with the source thickness, and it reaches peak energy depending on the density and the specific activity of the source. The beta flux and power output also increase with increasing source thickness. However, the incremental increase in beta flux and power output becomes minimal for higher thicknesses, as the source efficiency decreases significantly at higher thicknesses due to the self‐absorption effect. Thus, a saturation threshold is reached. A low‐density source material such as beryllium tritide provided a higher power output with higher efficiency. A maximum power output of approximately 4 mW/cm3 was obtained for beryllium tritide with SiC. A form factor approach was used to estimate the optimum source thickness. The optimum source thickness was found near the thickness where the peak beta particle average energy occurs. [ABSTRACT FROM AUTHOR]

Tritium beta-ray induced X-ray spectra in various gas mediums were simulated by Monte Carlo simulation using Geant4 tool kit. The simulated beta-ray induced X-ray spectrum (s-BIX spectrum) was composed of the bremsstrahlung component and characteristics X-rays from constituent elements. The total number of photons in s-BIX spectrum decreased with increasing pressure of medium except argon. In argon medium, the characteristics X-ray of argon was generated by beta particles from tritium decay, and the contribution of Ar-Kα and -Kβ compensated the reduction of bremsstrahlung generated by solid matter with increasing argon pressure. At 0.001 atm of medium pressure, the total counts in s-BIX spectrum was independent from gas medium. Therefore, the gas medium dependence in BIXS at low pressure (less than 0.001 atm) was not serious issue. [ABSTRACT FROM AUTHOR]

In beta emitters, in order to evaluate the absorbed dose rate at different tissue depths, it is necessary to determine the transmission factors. In this work, the transmission factors determined in beta secondary standard radiation beams are presented. For this purpose, an extrapolation chamber was used. The results obtained were considered acceptable, and they are within the uncertainties in comparison with the values provided by the source calibration certificate. The maximum differences between the results obtained in this work and those from the calibration certificate were 3.3%, 3.8% and 5.9% for 90 Sr/ 90 Y, 85 Kr and 147 Pm sources respectively. [ABSTRACT FROM AUTHOR]

Semiconducting carbon nanoparticles (CNPs) represent various applications in sensing systems with exceptional electronic properties. The extraction of electronic parameters of a sensor is very important to interpret the sensing characteristics of the electronic devices. This work is concerned with the extraction of electronic parameters such as the ideality factor, the barrier height, the series resistance, and some other diode parameters of a CNP-based metal semiconductor metal structure. The parameters are determined from the experimental data and physical model using the standard current-voltage (I-V) analysis in the frame of the thermionic emission theory, impedance spectroscopy, and other methods. The mobility-lifetime products (μτ) for electrons and holes in CNP micro-wire were determined by beta-ray-induced charge with Schottky contacts. [ABSTRACT FROM AUTHOR]

The multi-physics design of a five cell, β G = 0 . 61 , 644 MHz superconducting elliptical cavity being developed for an energy upgrade in the Facility for Rare Isotope Beams (FRIB) is presented. The FRIB energy upgrade from 200 MeV/u to 400 MeV/u for heaviest uranium ions will increase the intensities of rare isotope beams by nearly an order of magnitude. After studying three different frequencies, 1288 MHz, 805 MHz, and 644 MHz, the 644 MHz cavity was shown to provide the highest energy gain per cavity for both uranium and protons. The FRIB upgrade will include 11 cryomodules containing 5 cavities each and installed in 80-meter available space in the tunnel. The cavity development included extensive multi-physics optimization, mechanical and engineering analysis. The development of a niobium cavity is complete and two cavities are being fabricated in industry. The detailed design of the cavity sub-systems such as fundamental power coupler and dynamic tuner are currently being pursued. In the overall design of the cavity and its sub-systems we extensively applied experience gained during the development of 650 MHz low-beta cavities at Fermi National Accelerator Laboratory (FNAL) for the Proton Improvement Plan (PIP) II. [ABSTRACT FROM AUTHOR]

Atomic multipole moments associated with a spherical volume fully residing within a topological atom (i.e., the β sphere) can be obtained analytically. Such an integration is thus free of quadrature grids. A general formula for an arbitrary rank spherical harmonic multipole moment is derived, for an electron density comprising Gaussian primitives of arbitrary angular momentum. The closed expressions derived here are also sufficient to calculate the electrostatic potential, the two types of kinetic energy, as well as the potential energy between atoms. Some integrals have not been solved explicitly before but through recursion and substitution are broken down to more elementary listed integrals. The proposed method is based on a central formula that shifts Gaussian primitives from one center to another, which can be derived from the well‐known plane‐wave expansion (or Rayleigh equation). © 2018 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The oxide MgGa 2 O 4 spinel ceramics doped with Mn 2+ ions was synthesized by a solid-state reaction at 1200 °C in air. The activator concentration was equal 0.05 mol% of MnO. Phase purity of the synthesized samples was analyzed by X-ray diffraction technique. This spinel ceramics show efficient green emission in the range from 470 to 550 nm with a maximum at about 505 nm under UV or X-ray excitations, which is due to Mn 2+ ions. MgGa 2 O 4 : Mn 2+ exhibits intense thermoluminescence (TL) and optically stimulated luminescence (OSL) after influence of ionizing radiation. Are complex nature of the TL glow curves is associated with a significant number of structural defects that are responsible for the formation of shallow and deep electron traps. In this work, time-resolved OSL characteristics of the samples exposed to beta particles are reported for the first time. A light from green LED was used for optical stimulation. Obtained TL and OSL results suggest MgGa 2 O 4 :Mn 2+ as perspective material for further research and possible application in radiation dosimetry. [ABSTRACT FROM AUTHOR]

Here the geometries that maximise detection efficiency of heterogeneous scintillators used to detect beta particles in aqueous solutions by maximising energy deposition are described. The determination of the geometry was achieved with the Monte Carlo code Geant4 using CaF 2 :Eu scintillator as a pertinent case study, and validated with experimental data using single crystal CaF 2 :Eu and heterogeneous CaF 2 :Eu scintillators. Both 2D and 3D structures composed of arrays of primitive unit cells of packed spheres were examined to find the optimal geometry to maximise detection of volumetric sources of tritium and aqueous Carbon 14 and Lead 210. The 2D structures were evaluated relative to a single crystal scintillator and results show the detection efficiency of the 2D structures is maximised when the sphere radius is c.a. 0.46x the maximum track length of the beta particle in the scintillator. Data for the 3D structures show that the efficiency is maximised when the sphere radius is minimised, but it is further shown that practical issues limit the minimum radius that can be used for transient radiological contamination monitoring. [ABSTRACT FROM AUTHOR]

An in situ detection method for beta-ray distribution was developed. The method uses the gamma-ray sensitivity difference between two scintillators: a cadmium–tungstate (CdWO4) scintillator and a plastic scintillator. The gamma-ray sensitivity ratios for several gamma-ray sources such as 137Cs, 60Co, 22Na, and 54Mn were experimentally characterized. The sensitivity ratio for 137Cs between the CdWO4 and plastic scintillators was 8 ± 0.32, while the sensitivity ratio for beta rays from 90Sr was 1.03 ± 0.006. The beta-ray contributions to the total counts can be evaluated using this characteristic. A combined beta-ray and gamma-ray source was prepared, and its beta-ray distribution was successfully obtained using the proposed method. [ABSTRACT FROM AUTHOR]

Combustion synthesized nanocrystalline calcium oxide is irradiated with gamma rays, beta rays and swift heavy ions. TL glow curves of γ-irradiated samples show a prominent peak at 654 K with shoulder at 411 K. Whereas, β-irradiated samples exhibits two TL glows with peaks at 535 K and 570 K. TL glow peak intensity of β-irradiated samples increases linearly with increase in dose and position of glow peak temperature remains constant. TL of 120 MeV Au 9+ ion irradiated sample show similar glow curve structure to that of gamma irradiated one. However, TL mechanism of ion irradiated sample differs from gamma irradiated one and it is discussed in the text. The TL curves are deconvoluted to calculate kinetic parameters. Activation energy and frequency factor are in the range 0.70 eV to 1.40 eV and 4.49 × 10 7 to 2.85 × 10 9 s −1 respectively. [ABSTRACT FROM AUTHOR]

This article deals with the influence of electron-beam radiation on the micro-mechanical, thermo-mechanical, and structural properties of selected polymers. In the search for the desired improvement of polymers, it is possible to use, inter alia, one particular possible modification--Namely, crosslinking--Which is a process duringwhichmacromolecular chains start to connect to each other and, thus, create the spatial network in the structure. In the course of the treatment of the ionizing radiation, two actions can occur: crosslinking and scission of macromolecules, or degradation. Both these processes run in parallel. Using the crosslinking technology, standard and technical polymers can acquire the more "expensive" high-tech polymeric material properties and, thus, replace these materials in many applications. The polymers that were tested were selected from across the whole spectra of thermoplastics, ranging from commodity polymers, technical polymers, as well as high-performance polymers. These polymers were irradiated by different doses of beta radiation (33, 66, 99, 132, 165, and 198 kGy). The micro-mechanical and thermo-mechanical properties of these polymers were measured. When considering the results, it is obvious that irradiation acts on each polymer differently but, always when the optimal dose was found, the mechanical properties increased by up to 36%. The changes of micro-mechanical and thermo-mechanical properties were confirmed by structural measurement when the change of the micro-hardness and modulus corresponded to the crystalline phase change as determined by X-ray and gel content. [ABSTRACT FROM AUTHOR]

The intention of this study is to explore the thermoluminescence (TL) behavior of beta irradiated 5% Dy 3+ doped zinc borate (Zn(BO 2 ) 2 :0.05Dy 3+ ) phosphor prepared using the nitric acid method. The TL glow curve corresponding from 1 Gy to 80 Gy beta irradiation (preheated at 140 °C) shows a maxima at c.a. 180 °C. The dependence of heating rate was tested and found out that thermal quenching effect was dominating on TL glow curves as the heating rate increases. The dose response of the phosphor material exposed to beta radiation was investigated. Deconvolution was applied using the peak fit method on the glow curve for optimized conditions. Also peak shape (PS), various heating rates (VHR) and computerized glow curve deconvolution (CGCD) methods were used to evaluate the trapping level parameters, namely trap depth ( E ), frequency factor ( s ) and order of kinetics ( b ) associated with the main glow curve in Zn(BO 2 ) 2 :0.05Dy 3+ phosphor after beta irradiation of 20 Gy. The values of trap depth corresponding with the TL glow peak at 180 °C were found to be 0.93 eV, 0.92 ± 0.05 and 1.05 ± 0.02 respectively. Furthermore W and c parameters characterizing thermal quenching based on the Mott-Seitz theory were determined as 0.31 ± 0.04 eV and 162.55. The TL mechanism appears more likely to get second order kinetics, suggesting the probability of re-trapping of charge carriers by emptied traps. [ABSTRACT FROM AUTHOR]

Ra-223 has recently been introduced in alpha-targeting radionuclide therapy. According to the decay scheme of Ra-223, beta particles with higher energy than the Cerenkov-light threshold are emitted. In addition, there are reports that the alpha particles themselves emit luminescence in water and air. However, measured optical imaging results from Ra-223 have not yet been reported. Therefore, we conducted optical imaging of an Ra-223 solution and compared it with that of an F-18 solution. Ra-223 and F-18 solutions contained in transparent glass vials were imaged using a high-sensitivity CCD camera. We could obtain an image of the Ra-223 solution with radioactivity of 0.72 MBq in an acquisition time of less than 10 s. At the same level of radioactivity, the intensity of the optical signal in the solution part of the vial of Ra-223 was 21 times higher than that of F-18. Furthermore, in the air part of the vials, Ra-223 had higher luminescence than that of F-18. The light spectra for Ra-223 and F-18 solutions were similar, but those in the vials' air parts were different. The optical signals in the solution part of both Ra-223 and F-18 are attributed to Cerenkov light, while that in the air part of Ra-223 is attributed to the scintillation of N 2 gas in air. No obvious luminescence of water by the alpha particles was observed. We concluded that optical imaging of the Ra-223 solution was possible, and this solution's light intensity was much higher than that of the F-18 solution and thus easier to detect. Therefore, Ra-223 is a promising radionuclide for optical imaging in distribution measurements. [ABSTRACT FROM AUTHOR]

In this study, gross alpha and beta radioactivity in food crops and surface soil collected from Ho Chi Minh City, Vietnam were measured. Based on the annual effective dose from ingestion of food crops, the degree of risk to human health was estimated. We found out that the obtained values of the dose do not exceed the WHO recommended level (290 µSv year). The estimated soil-to-plant transfer factors for gross alpha (TF) and beta (TF) for food crops were also presented. It was found that TF varied in the range from 0.009 ± 0.005 to 0.99 ± 0.06, TF varied in the range from 2.26 ± 0.10 to 10.87 ± 0.53 and the maximum values of transfer factors were found in the root of ipomoea batatas. [ABSTRACT FROM AUTHOR]

This work reports the persistent luminescence (PersL) properties of the commercial LiF:Mg,Ti (TLD-100) dosimeter and its performance in dosimetry applications. The thermoluminescence (TL) glow curve of the TLD-100 exhibits a peak at 96 °C that rapidly vanishes at room temperature, enabling the PersL phenomenon. The TLD-100 was exposed to beta particle irradiation within in the range of 0.22–32 Gy. The resulting PersL intensity was measured and found to increase as the irradiation dose increased. Notably, there was no saturation of the PersL intensity within this dose range with linear dependence from 0.55 to up 32 Gy. The TLD-100 showed good repeatability with a deviation of 0.1% after seven irradiation-readout cycles for twenty irradiations. The calculated lower detection limit was 2 mGy. Our results indicate that the TLD-100 can be used as a PersL and TL dosimeter for dosimetry applications, with the advantages of fast post-irradiation measurements. • The persistent luminescence of a commercial TLD-100 dosimeter after beta particle irradiation is presented. • The persistent luminescence intensity increased with increasing irradiation dose from 0.55 to 32 Gy with linear dependence. • The calculated lower detection limit was 2 mGy for TLD-100 using persistent luminescence phenomenon. • The persistent luminescence could be complementing the traditional TL dosimetry method. [ABSTRACT FROM AUTHOR]

In 2012, the International Commission on Radiological Protection recommended a reduction of the equivalent dose limit for the lens of the eye from 150 mSv to 50 mSv per year, with a maximum 5-year average of 100 mSv. This noticeable reduction imposes more demands on the performance on personnel eye-lens dosimetry. Regulatory authorities of various jurisdictions worldwide followed some or all, of the ICRP recommendations and implemented reduced occupational lens of eye dose limits in their legislation. Commercial dosimetry service providers have risen to the challenges by developing new dosemeter technologies, and some in-house dosimetry services have developed their own eye-lens dosemeters. The results of the energy and angular response, to photon and beta radiation, of three commercial dosemeters are reported here. Their performances are compared to those of the dosemeter developed, in-house, by Canadian Nuclear Laboratories. With some adjustments to their calibrations, the responses of all dosemeters, could be within the performance limits set by the ISO 14146 and the IEC 62387 standards for the conditions of the tests that were performed. • Commercial eye lens dosemeters have been tested for photons and beta particles. • Most dosemeters provide energy and angular responses within or close to the ISO and IEC limits. • The tested dosemeters can provide conservative eye-lens dose estimates in mixed photon/beta fields. [ABSTRACT FROM AUTHOR]

This work reports for the first time on the thermoluminescence (TL) and persistent luminescence (PLu) characterization of BaZrO 3 synthesized through solid state reaction. X-Ray diffraction confirmed the crystalline structure of the synthesized phosphors. The characteristic glow curves of the synthesized samples exhibit TL maxima located at 85 and 165 °C, whose fading after radiation exposure gives rise to intense PLu. PLu decay curves were recorded after beta particle irradiation in the dose range from 1.0 up to 1024 Gy. Both TL and PLu exhibit remarkable reproducibility. The integrated persistent luminescence (IPLu) as a function of the irradiation dose exhibits a linear dependence in the 1.0–16 Gy dose range, followed by a sublinear behavior from 16 to 128 Gy. From the experimental evidence here presented, it is concluded that solid state synthesized BaZrO 3 is an interesting phosphor material to be implemented as a PLu-based detector and dosimeter. • Thermoluminescence (TL) and persistent luminescence (PLu) features of solid-state synthesized BaZrO 3 phosphors are reported. • The synthesized BaZrO 3 phosphors exhibit PLu features suitable for non-thermoluminescence dosimetry. • Both, TL and PLu of beta-irradiated BaZrO 3 exhibit remarkable reproducibility. [ABSTRACT FROM AUTHOR]

Through traditional high-temperature combustion synthesis, a series of luminescent orange-red emitting Sr 2 YVO 6 :Eu3+ double perovskite phosphors were prepared, and their luminescence properties were examined. Through X-ray diffraction (XRD) and Rietveld analysis, the monoclinic crystal structure of all prepared Sr 2 YVO 6 :Eu3+ phosphors were confirmed. Scanning electron microscopy (SEM) was used to analyse the morphology of the phosphor. Under 320 nm excitation, Eu3+ doped Sr 2 YVO 6 phosphors exhibit very strong red photoluminescence (PL) emission bands at 595 nm, 616 nm and 620 nm as well as distinct red emission bands at 653 nm and 699 nm, which are originated due to the 5D 0 -7F J (J = 1,2,3,4) transition of Eu3+. A series of phosphor also exhibit orange-red emission at 595 nm, 612 nm, 616 nm and 620 nm under the excitation wavelength of 396 nm. High color purity of the phosphors is revealed by calculated color purity and excellent chromaticity coordinates, which also confirms the presence of far-red luminescence emission. After the irradiation of the phosphors at various beta doses via 90Sr/90Y beta source, the thermoluminescence (TL) studies of Eu3+ activated Sr 2 YVO 6 phosphors was conducted. Exposer of beta irradiation revises a prominent TL glow curve at 124 °C with a small hump at around 290 °C, indicating the development of different trap centres in the phosphor. As the dose of beta radiation increased, a linear dose response was observed in TL intensity. Computerised Glow Curve Deconvolution (CGCD) method and Chen's Peak Shape Method (PSM) were used to determine the activation energies and trapping parameters of TL glow curves. According to CGCD fitting of TL glow curves, it is found that all glow curves consist of five deconvoluted peaks, which follows general order kinetics. Activation energies calculated through different methods were comparable and significant. • A series of double perovskites Sr 2 YVO 6 doped with Eu3+ were synthesized successfully through combustion synthesis. • XRD, SEM, and FTIR characterization techniques were used to conduct structural and morphological analysis. • Intense red emission under 320 nm excitation wavelength reveals high potentiality of the phosphor in display devices. • TL studies of the double perovskite phosphors were performed after exposing the samples to various beta ray doses. • In the dose range of 1 Gy–10 Gy of beta rays, a linear TL response with increasing beta dose was observed. [ABSTRACT FROM AUTHOR]

• The α-alumina unit cell volume increase with beta radiation up to 110 Gy. • Thermoluminescence intensity changes with applied dose. • Distortion decreases and α-Al 2 O 3 unit cell increases till a dose of 110 Gy. • Thermoluminescence intensity is correlated to structure distortion. Dosimetry is a field that deals with detection of ionizing radiation through studying widespread of materials and the influence and quantification of this radiation on the electronic configuration and structure of these materials. A major parameter that determines the quality of dosimeters and affects its performance is the imperfections found in the crystal structure. In this paper, we present the effects of radiation with beta particles on the structural properties of α-alumina. The samples were irradiated to different doses from 5.5 Gy up to 1100 Gy. Although all the compounds showed the hexagonal crystal structure, but it was observed the unit cell volume as well as the lattice parameters increase with radiation dose till 110 Gy. Moreover, corresponding to that increase in the lattice volume a simultaneous decrease in the TL intensity was observed to reach its minimum at the same dose then increase slightly; this behavior corresponds to an opposite trend with the lattice parameters. This effect can be assigned to the distortion in the structure upon radiation with beta particles and hence the decrease in the TL sensitivity. [ABSTRACT FROM AUTHOR]

This work reports on the beta particle excited thermoluminescence (TL) of ZnO:Ce phosphors, synthesized through a controlled chemical precipitation reaction followed by thermal annealing at 900 °C in an air atmosphere during 24 h. The successful obtention of crystalline hexagonal zincite structure was confirmed by X-Ray diffraction. By milling ZnO:Ce powder precipitated during the reaction before carrying out the thermal annealing, there are improved reproducibility and enhanced TL features of interest for dosimetry. Ce doping strongly increases the TL sensitivity and leads to a simpler glow curve shape. The TL – dose response exhibits a linear behavior at least up to 128 Gy. The sensitivity of the synthesized ZnO:Ce is ca. 103 times greater than that of undoped ZnO. The TL fades 22% two days after radiation exposure, and then it becomes negligible. • ZnO:Ce phosphors exhibit thermoluminescence (TL) features suitable for TL dosimetry. • Ce-doping remarkably improves the TL features of ZnO interesting for TL dosimetry. • Milling of the chemically synthesized ZnO:Ce before thermal annealing favors TL peaks suitable for dosimetry applications. [ABSTRACT FROM AUTHOR]

Simulation of beta particle transport from a Ni-63 radioisotope in silicon using the Monte Carlo N-Particle (MCNP) transport code for monoenergetic beta particle average energy, monoenergetic beta particle maximum energy, and the more precise full beta energy spectrum of Ni-63 were demonstrated. The beta particle penetration depth and the shape of the energy deposition varied significantly for different transport approaches. A penetration depth of 2.25±0.25 µm with a peak in energy deposition was found when using a monoenergetic beta particle average energy and a depth of 14.25±0.25 µm with an exponential decrease in energy deposition was found when using a full beta energy spectrum and a 0° angular variation. For a 90° angular variation, i.e. an isotropic source, the penetration depth was decreased to 12.75±0.25 µm and the backscattering coefficient increased to 0.46 with 30.55% of the beta energy escaping when using a full beta energy spectrum. Similarly, for a 0° angular variation and an isotropic source, an overprediction in the short circuit current and open circuit voltage solved by a simplified drift-diffusion model was observed when compared to experimental results from the literature. A good agreement in the results was found when self-absorption and isotope dilution in the source was considered. The self-absorption effect was 15% for a Ni-63 source with an activity of 0.25 mCi. This effect increased to about 28.5% for a higher source activity of 1 mCi due to an increase in thickness of the Ni-63 source. Source thicknesses of approximately 0.1 µm and 0.4 µm for these Ni-63 activities predicted about 15% and 28.5% self-absorption in the source, respectively, using MCNP simulations with an isotropic source. The modeling assumptions with different beta particle energy inputs, junction depth of the semiconductor, backscattering of beta particles, an isotropic beta source, and self-absorption of the radioisotope have significant impacts in betavoltaic battery design. [ABSTRACT FROM AUTHOR]

A computerized tomography (CT) system using a 0.1μCi Sr-90 beta source, Geiger counter, and low density foam samples was developed. A simple algorithm was used to construct images from the data collected with the beta CT scanner. The beta CT system is analogous to X-ray CT as both types of radiation are sensitive to density variations. This system offers a platform for learning opportunities in an undergraduate laboratory, covering topics such as image reconstruction algorithms, radiation exposure, and the energy dependence of absorption. [ABSTRACT FROM AUTHOR]

The influence of high doses of beta radiation on the changes in the structure and selected properties (mechanical and thermal) polymers were proved. Using high doses of beta radiation for polybutylene terephthalate (PBT) and its influence on the changes of mechanical properties of ultra nanohardness has not been studied in detail so far. The specimens of polybutylene terephthalate (PBT) were made by injection moulding technology and irradiated by high doses of beta radiation (0, 33, 66 and 99 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using FTIR, WAXS and instrumented ultra nanohardness test. The results of the measurements showed considerable increase in mechanical properties (indentation hardness, indentation elastic modulus) when the high doses of beta radiation are used. [ABSTRACT FROM AUTHOR]

DURAMID with 45% of glass fibre (PA 9T) have been successfully modified using beta rays. PA 9T samples were prepared by injection moulding technology and then were irradiated from 33 to 198 kGy in electron accelerator RHODOTRON. The thermal properties (e.g. DSC and TGA) of modified PA 9T samples by beta rays were measured. The tested samples showed significant changes of thermal properties after irradiation. From this point of view, new applications could also be seen in areas where more expensive materials (metals, composites etc.) are used, especially for application in automotive and military industry. [ABSTRACT FROM AUTHOR]

The polypropylene samples for testing were injection moulded and subsequently irradiated by beta radiation at the dose of 15 and 33 kGy with the kind help of BGS Germany. Temperature stability, tensile test, bending test and Charpyimpact test were applied. The influence of beta irradiation low doses on thermal and mechanical properties was subsequently compared. Just dose of irradiation 15 kGy improves tensile and bending properties of polypropylene which expands usage of this material in new applications, especially in automotive. [ABSTRACT FROM AUTHOR]

Values of the new protection quantity 'Local Skin Dose' LSD, introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β- or β+ emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H'(0.07,0°), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. [ABSTRACT FROM AUTHOR]

Positron attenuation tomography (PAT) is a new modality for imaging the linear attenuation coefficients (LACs) of magnetically constrained \beta ^+ -ray beams in matter. A complete 3-D LAC image of an object can be made by measuring the positron annihilation rate density within it at a single orientation relative to the beam, and then applying the PAT transformation. The spatial resolution of this image is limited by the resolution of the positron emission tomography (PET), or other, system used to acquire the data as well as the scattering and gyration of the positrons around the magnetic field lines. The finite resolution of the PET system also leads to nonlinear artifacts associated with extended LAC discontinuities parallel to the beam. The mass thickness of an object that can be imaged is limited by the positron beam’s range in it. However, due to the directional nature of the imaging process as well as its discrete sampling, PAT images acquired at different view angles may each carry unique information on the object’s structure. This paper describes a forward model of PAT image formation and a backpropagation algorithm that, when used together to iteratively combine the data from multiple views, can improve the spatial resolution of PAT LAC images, extend their effective field of view, and reduce artifacts. The technique is demonstrated on measured and simulated data. [ABSTRACT FROM PUBLISHER]

This paper aims to show how the variance reduction technique “Geometry splitting/Russian roulette” improves the statistical error and reduces uncertainties in the determination of the absorbed dose rate in tissue using an extrapolation chamber for beta radiation. The results show that the use of this technique can increase the number of events in the chamber cavity leading to a closer approximation of simulation result with the physical problem. There was a good agreement among the experimental measurements, the certificate of manufacture and the simulation results of the absorbed dose rate values and uncertainties. The absorbed dose rate variation coefficient using the variance reduction technique “Geometry splitting/Russian roulette” was 2.85%. [ABSTRACT FROM AUTHOR]

Liquid scintillation spectrometry (LSS) is a meaningful technique for the determination of alpha and beta emitters. However, this technique is highly affected by quenching phenomena, which reduce the counting efficiency, shift the spectra to low energies and cause misclassification problems. In this paper, a selection of chemical and colour quench agents was evaluated to study the influence of alpha and beta energy and the quenching effect on the detection efficiency, the shape of the spectra and the α/β misclassification. [ABSTRACT FROM AUTHOR]

We assessed the accuracy of mono-energetic electron and beta-emitting isotope dose-point kernels (DPKs) calculated using the particle and heavy ion transport code system (PHITS) for patient-specific dosimetry in targeted radionuclide treatment (TRT) and compared our data with published data. All mono-energetic and beta-emitting isotope DPKs calculated using PHITS, both in water and compact bone, were in good agreement with those in literature using other MC codes. PHITS provided reliable mono-energetic electron and beta-emitting isotope scaled DPKs for patient-specific dosimetry. [ABSTRACT FROM AUTHOR]